Visual prostheses have been developed to restore vision within blind or partially blind patients. A visual prosthesis commonly includes an implantable component including an electrode array, situated on or in a substrate, for placement in the eye on or near retinal cells. Electrical signals are transmitted via the electrodes to the retinal cells, triggering a perception of light within the patient's brain. The prosthesis can therefore restore vision to patients whose retinal photoreceptors have become dysfunctional.
Commonly, a visual prosthesis is used in conjunction with a video camera. A stream of images detected by the camera is converted into digital signals by an image processor and transmitted in ‘real time’ to an electrode interface unit. The electrode interface unit is connected to the electrode array via a plurality of conductors and decodes the signals and stimulates the electrodes in accordance with the detected images.
The digital signals can be transmitted wirelessly, at least part or all of the way between the processor and the implantable component. A wireless receiver for receiving the wireless signals can be located on the substrate, or separate to the substrate.
The substrate of the prosthesis can be located in a variety of positions to stimulate the retina. One approach is to place the electrode-carrying part of the substrate between the sclera and the choroid, i.e. into the suprachoroidal space. For example, US 2009/0177245 A1 and US 2006/0074461 A1 each disclose an electrode array placed suprachoroidally, the electrode array being connected via a connecting cable, extending through an incision in the sclera, to an interface unit located to the outside of the sclera (i.e., episclerally). The cable takes the form of a ribbon cable, comprising a plurality of wires connecting individual electrodes to the interface unit.
Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
Throughout this specification the term “visual prosthesis” is used to denote apparatus for restoring or improving a patient's vision, and will be understood to include devices otherwise known as bionic eyes, artificial eyes, retinal prostheses and retinal stimulators or similar.